Electron Density Analysis

Over the last 40 years, the theory of dynamical systems has inspired a continuous development of theoretical tools of analysis of the electron density as well as other related scalar local functions obtained either from experiment or from quantum chemical calculations. These topological approaches enable the improvement of the definition of many chemical concepts related to the theory of chemical bonding as well as the introduction of new concepts. In this way, they contribute to the construction of an epistemological bridge between the quantum mechanics and the phenomenological description of the matter proper to chemistry. They also provide qualitative and quantitative criteria for the characterization of chemical bonding and give access to measures of electron delocalization in chemical systems or in fragments of chemical systems. Although fewmarginal examples of predictive applications of these topological analyzes exist, their main objective is to propose a precise description of the distribution of the electron density in order to explain the properties of the investigated system. In this way, the topological approaches must be understood as complementary to rather than concurrent with themolecular orbital and the valence-bond theories of the molecular/crystalline structure and reactivity. These methods, which display pictorially the electron distribution, can be very useful to teach structural chemistry to first year undergraduate students